Study ties blood-pressure drugs to breast cancer

WOMEN taking a common class of drugs to control high blood pressure - called calcium channel blockers or calcium antagonists - may more than double their risk for breast cancer if they continue the medication for longer than a decade.

This US-based observational study, published in JAMA Internal Medicine, found that women aged 55 to 74 who took calcium antagonists - medication used to prevent heart attacks and strokes - for 10 years or more had two and a half times the risk of developing breast cancer than women who treated hypertension with other medication and women who had never taken hypertension medication at all.

The study was led by Dr. Christopher Li of the Fred Hutchinson Cancer Research Center in Seattle. It is the first study that has found a link between the long-term use of calcium channel blockers and a higher risk of breast cancer. The research team surveyed 1,763 women in the Seattle area who had been diagnosed with the two most common types of breast cancer: invasive ductal carcinoma and invasive lobular carcinoma between 2000 and 2008. Researchers investigated the women’s medication use prior to their breast cancer diagnosis, which led to the study’s findings.

Kathleen Malone, co-author of the study, said the outcome of the research should not prompt women to stop taking their prescribed calcium channel blockers.

“With this kind of research, it’s really important to make sure that results are confirmed,” she said. “Treating hypertension is so important that the last thing we want to do is start changing people’s priorities when we really need more replication of this result first.”

If the results of this study can be replicated in the longer term, Malone said patients might consider some of the other options available for treating hypertension, but for now, it is too early to make changes to treatment plans based on the study.

Researchers found that other drugs used to treat hypertension including angiotensin-converting-enzyme (ACE) inhibitors, beta blockers and diuretics were not linked to breast cancer risks.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment.